Originally Posted by
Chu Chu
Maybe the angles are different for a hard landing?
The geometry limit graph is a rigid body solution, e.g., it is a static clearance outcome. The dynamic solution can be different for other parts of the aircraft. The compressed oleo geometry is a limit if the gear stays in one piece. The aft body does have bending under inertial load and from the interaction of gear load v elevator/horizontal stab loads, but they are not very large. A significant change does occur for the engine cowl clearance as a response to gear loads and timing of the resultant torsion of the wing box and the engine pylon. I have investigated a couple of landings where a pod scrape occurred well within the geometry envelope, but the pod still moved enough with the wing to touch the pod on the ground. The process of those institutionally was interesting, the system wanted to hang a bunch of crews trying to ascertain why they had not picked up the damage on the intervening flights, as in both cases they didn't want to accept that the last crew who did hard landings with low pitch attitude and roll were responsible. The OEM responded in both cases confirming the geometry was a static model... which raised furore within the company as being misleading to their fine crew. 3g landings on one wheel near a geometry limit for both pitch and roll may result in a visit to the spray booth.